This invention pertains to electrically operated hygienic apparatus such as toothbrushes, face massagers and the like, and more particularly, to a constant-speed variable-torque motor for the same.
In copending, commonly assigned patent application Ser. No. 420,298 filed Sept. 20, 1982, an oscillating a.c. motor is described which is particularly adapted for hygienic devices. More particularly the motor is designed so that its mechanical components are chosen to oscillate at a frequency which is equal to or slightly below the frequency of the a.c. electric power supply. It was found that using this principle stronger motors could be built which occupy relatively smaller spaces. However on further consideration, it was found to be desirable to make the motor with a variable torque and/or angle of operation. For example, if the motor is used in an electric toothbrush, the angle of operation should be varied depending on the age of the user and or other considerations. Inherently small children, persons suffering from periodontitis, or wearers of orthodontic appliances should use the toothbrush at a lower operating angle or torque than normal users. If the motor is used in a hand-held face massager, or skin care treatment device, its angle of operation torque should be varied in accordance with the accessory used and the area of the face or body being treated by the device. For example if a pad is used as an accessory to clean and moisturize skin, a relatively low angle of operation is required for a gentle treatment. On the other hand in general a massaging accessory requires a higher operational angle, except around certain sensitive areas such as the eyes or the forehead.